CD158 antigen like family member B2, CD158 antigen-like family member B2, CD158b, CD158b2, GL183, KI2L3_HUMAN, Killer cell immunoglobulin like receptor two domains long cytoplasmic tail 3, Killer cell immunoglobulin-like receptor 2DL3, Killer inhibitory receptor cl 2-3, Killer inhibitory receptor CL2 3, KIR 023GB, KIR-023GB, KIR-K7b, KIR-K7c, KIR023GB, KIR2DL3, KIR2DS5, KIRCL23, MHC class I NK cell receptor, Natural killer associated transcript 2, Natural killer cell inhibitory receptor KIR2DL3, Natural killer-associated transcript 2, NKAT, NKAT-2, NKAT2, NKAT2a, NKAT2b, p58, p58 natural killer cell receptor clone CL 6, p58 natural killer cell receptor clone CL-6, p58 NK Receptor, p58 NK receptor CL 6, p58 NK receptor CL-6, p58.2 MHC class I specific NK receptor, p58.2 MHC class-I-specific NK receptor

Killer cell immunoglobulin-like receptors (KIRs) are transmembrane glycoproteins expressed by natural killer cells and subsets of T cells. The KIR genes are polymorphic and highly homologous and they are found in a cluster on chromosome 19q13.4 within the 1 Mb leukocyte receptor complex (LRC). The gene content of the KIR gene cluster varies among haplotypes, although several framework genes are found in all haplotypes (KIR3DL3, KIR3DP1, KIR3DL4, KIR3DL2). The KIR proteins are classified by the number of extracellular immunoglobulin domains (2D or 3D) and by whether they have a long (L) or short (S) cytoplasmic domain. KIR proteins with the long cytoplasmic domain transduce inhibitory signals upon ligand binding via an immune tyrosine-based inhibitory motif (ITIM), while KIR proteins with the short cytoplasmic domain lack the ITIM motif and instead associate with the TYRO protein tyrosine kinase binding protein to transduce activating signals. The ligands for several KIR proteins are subsets of HLA class I molecules; thus, KIR proteins are thought to play an important role in regulation of the immune response.